feat: add modular services and repositories for improved code organization

Introduce repository pattern across multiple services, including `favorites`, `tags`, `sessions`, `reports`, `auth`, and more. Decouple crypto functionalities into modular services like `HashingService`, `JwtService`, and `EncryptionService`. Improve testability and maintainability by simplifying dependencies and consolidating utility logic.

backend/src/api-keys/repositories/api-keys.repository.ts

@@ -0,0 +1,58 @@
+import { Injectable } from "@nestjs/common";
+import { and, eq } from "drizzle-orm";
+import { DatabaseService } from "../../database/database.service";
+import { apiKeys } from "../../database/schemas";
+
+@Injectable()
+export class ApiKeysRepository {
+	constructor(private readonly databaseService: DatabaseService) {}
+
+	async create(data: {
+		userId: string;
+		name: string;
+		prefix: string;
+		keyHash: string;
+		expiresAt?: Date;
+	}) {
+		return await this.databaseService.db.insert(apiKeys).values(data);
+	}
+
+	async findAll(userId: string) {
+		return await this.databaseService.db
+			.select({
+				id: apiKeys.id,
+				name: apiKeys.name,
+				prefix: apiKeys.prefix,
+				isActive: apiKeys.isActive,
+				lastUsedAt: apiKeys.lastUsedAt,
+				expiresAt: apiKeys.expiresAt,
+				createdAt: apiKeys.createdAt,
+			})
+			.from(apiKeys)
+			.where(eq(apiKeys.userId, userId));
+	}
+
+	async revoke(userId: string, keyId: string) {
+		return await this.databaseService.db
+			.update(apiKeys)
+			.set({ isActive: false, updatedAt: new Date() })
+			.where(and(eq(apiKeys.id, keyId), eq(apiKeys.userId, userId)))
+			.returning();
+	}
+
+	async findActiveByKeyHash(keyHash: string) {
+		const result = await this.databaseService.db
+			.select()
+			.from(apiKeys)
+			.where(and(eq(apiKeys.keyHash, keyHash), eq(apiKeys.isActive, true)))
+			.limit(1);
+		return result[0] || null;
+	}
+
+	async updateLastUsed(id: string) {
+		return await this.databaseService.db
+			.update(apiKeys)
+			.set({ lastUsedAt: new Date() })
+			.where(eq(apiKeys.id, id));
+	}
+}